The present invention relates to the production of polyesters from polyketones.
Polyketones, i.e., polymers having carbonyl groups incorporated in the polymer chain, are known in the art and are most commonly produced by polymerizing carbon monoxide with one or more .alpha.-olefins. Polyketones of the type derived from ethylene and carbon monoxide were disclosed by Brubaker in U.S. Pat. No. 2,495,286. Numerous other liquid and gas phase procedures utilizing Ziegler and radical catalyst have been described in the prior art for polymerizing carbon monoxide with ethylene and other olefinically unsaturated monomers. A general review of the properties, preparations, reactions and uses of olefin-carbon monoxide copolymers can be found in the Encyclopedia of Polymer Science and Technology, Vol. 9, pp. 397-402, John Wiley & Sons, Inc. (1968).
Various procedures are known for the chemical modification of polyketones. U.S. Pat. No. 2,457,271 discloses a method for modifying monoolefin-carbon monoxide copolymers to increase the degree of unsaturation by heating the copolymer in a solution of an organic solvent with a minor amount of an alkaline metal hydroxide. The copolymer is reacted until the oxygen content is decreased by at least 5% or the iodine number increased to at least 25. Modification of polyketones (monoolefin-carbon monoxide copolymers) by reaction with hydrazine hydrate and related nitrogen-containing compounds is described in U.S. Pat. No. 2,457,279. A process for reacting polyketones with hydrogen cyanide to prepare polycyanohydrin resins is disclosed in U.S. Pat. No. 2,495,284.
U.S. Pat. No. 2,495,292 discloses the catalytic hydrogenation of monoolefin-carbon monoxide polymers in the presence of a nickel catalyst to reduce the carbonyl groups to secondary alcohol groups and obtain high molecular weight polyhydric alcohols. U.S. Pat. No. 2,846,406 relates to a process for reacting monoolefin-carbon monoxide copolymers with formaldehyde and specific ammonium or amine salts to produce polyamines of relatively high molecular weight. Another process for modifying monoolefin-carbon monoxide copolymers by reacting with hydrazoic acid in the presence of an acid catalyst is disclosed in U.S. Pat. No. 3,068,201.
Processes for producing thermoplastic polymers form polyketones are also disclosed in U.S. Pat. Nos. 3,979,373 and 3,979,374. The products of U.S. Pat. No. 3,979,373 are polymer furan derivatives obtained by reacting an equimolar alternate copolymer of ethylene and carbon monoxide with a strong acid, e.g. sulfuric, phosphoric, p-toluene sulfonic, etc., at 40.degree. to 200.degree. C. The polymeric pyrrollic polymers of U.S. Pat. No. 3,979,374 are obtained by reacting an equimolar alternate copolymer of ethylene and carbon monoxide with a primary monoamine in the presence of strong acid and a solvent at a temperature from 40.degree.-100.degree. C.
However, despite the variety of processes described above, the art as yet lacks a process that allows carbonyl groups incorporated into the polymer chain of a polyketone to be readily oxidized to ester groups.
U.S Pat. Nos. 4,929,711 and 4,957,997 to Chang et al. describe processes for converting polyketones to polyesters by reacting a polyketone with an organic peroxyacid oxidizing agent in an inert liquid medium. The conversions in these processes typically require over an hour to achieve desirable results. However, these processes are not practical from a commercial standpoint, because they cannot be readily adapted to mass production of polyesters.